Thermostat



Oct. 16, 1934. G. R. BLODGETT 1,977,570

THERMOSTAT Filed April 30, 1932 I INVENTOR GEORGE R. BLODGETT BY HIS ATTORNEYS Patented Oct. 16, 1934 UNITED STATES PATENT OFFICE THERMOSTAT George R. Blodgett, Toledo, Ohio, assignor to Moto Meter Gauge & Equipment Corporation, Toledo, Ohio, a corporation of Delaware Application April 30, 1932, Serial No. 608,509

8 Claims. (01. 236-34) This invention relates to thermostats and more particularly to temperature responsive devices of the expansible chamber type, which are adapted to actuate mechanism of various kinds, in response to changes in temperature in various installations.

The main object of the invention is to provide a thermostat which will have a quick action at the temperature at which it is desired to be actuated.

Further objects are to simplify and improve the construction and operation of thermostats of this character, to render them economical to manufacture, reliable and convenient in use, and otherwise well adapted for the purposes set forth.

Other objects and features of novelty will be apparent as the following description proceeds, reference being had to the accompanying drawing, in which Figure 1 is an end elevation of a thermostat according to the preferred embodiment of the invention;

Figure 2 is a section taken along the line 22 of Figure 1;

Figure 3 is a view similar to Figure 1, but showing the thermostat in the expanded position; and

Figure 4 is a section taken along the line 4-4 of Figure 3.

The expansible chamber is illustrated as a Bourdon tube 10, which maybe nearly a complete circle and is preferably oval incross-section. The ends of the Bourdon tube 10 are connected to two relatively movable members, so as to cause relative movement thereof at the temperature at which the-thermostat is desired to operate.

One end of the Bourdon tube 10 is connected to a support 11, and the other end of the tube 10 is connected to a device 12 which is to be operated by the thermostat. In the form shown, the support 11 is an annular member which is adapted to be installedin the cooling system of an internal combustion engine, such as an automobile motor, and the device 12 is a butterfly valve which prevents or retards the circulation of the cooling medium during the warm up period. The annular member 11 is so mounted that in the closed position of the valve 12, the Bourdon tube 10 is in the portion of the cooling system which is at the higher temperature, i. e., nearest to the water jacket of the engine. The valve 12 thus separates the Bourdon tube from the portion of the cooling system which is at a relatively lower temperature, being nearer to the automobile radiator.

The ends of the Bourdon tube 10 are closed by end caps 13 and 14, and the tube is preferably supported entirely by means of these caps. The end cap 13 is pivoted on a pin 15 which is suitably attached to the support 11, while the end cap 14 is pivoted by means of a pin 16 to a rigid portion of the butterfly valve 12. This valve is pivoted as by means of a shaft 17 in the wall of the support 11, and the rigid portion which receives the pivot 16 comprises an arm 18.

With the arrangement described above, the Bourdon tube is supported entirely by the pivots 15 and 16, which are parallel to each other and parallel to the axis of the Bourdon tube and the shaft 17. Thus, freedom of movement in the plane of the Bourdon tube is provided, while at the same time lateral movement is prevented. The move. ment due to expansion of the Bourdon tube is substantially along a line through the pivots 15 and 16 although the pivot 16 is constrained to move in an are about the pivot 1'7. The pivot 16 is so located that the movement of the valve 12 from the closed position of Figure 2 to the open position of Figure 4 may take place without moving the pivot 16 materially out of the line through this pivot and the pivot 15. The absence of any linkage eliminates lost motion and insures that movement of the Bourdon tube 10 will cause a responsive movement of the shutter 12.

The Bourdon tube 10 is preferably filled with a material which melts at a temperature near that at which it is desired to operate the shutter. This 5 material also has the quality of changing materially in volume when it is melted, so that it occupies a larger or smaller volume in the liquid state than that occupied in the solid state.' These qualities of the filling material add to the desired,

quick acting characteristic of the thermostat.

There is a range of materials which is available as the filling material for the tube 10. For

actuation at a temperature between 150 and 160 F., the tube 101s filled with 96% diphenyl and 4% diphen'yl amine. Pure beeswax can be used as a filling medium if it is desired to have the quick action take place at a temperature of about 142 F. For higher temperatures carnauba wax is preferred. Mixtures of beeswax and carnauba wax in 100 diiferent proportions can be compounded to provide an operating temperature at a desired point between 142 and .185 F. Certain alloys and organic and inorganic compounds with distinct melting points and ability to change their volume in changing from the solid to the liquid state, can be used in order to obtain a response at any temperature desired.

The tube 10 may be filled according to the method described in the copending application 11 Serial No. 593,380 for Quick action thermostats, flled jointly by Adrian Brietzke and myself on February 16th, 1932.

The invention embraces such embodiments of the disclosed ideas as fall within the scope of the appended claims.

- I claim:

1. In combination with an annular member having a butterfly valve pivoted therein, a Bourdon tube having one end pivoted to said annular member and the other end pivoted to said butterfly valve, said pivots being of sufficient lateral extent'for preventing lateral movement of said Bourdon tube. v A

2. In combination with an annular support and a butterfly valve pivoted therein, a Bourdon tube extending nearly a complete circle, and means for mounting said Bourdon tube for pivotal movement with respect to both said support and said butterfly valve in the plane of said Bourdon tube, said means also serving to prevent lateral movement of the Bourdon tube.

3. In combination with an annular support and a butterfly valve pivoted therein, a Bourdon tube having end caps, means connecting one end cap of said Bourdon tube to said butterfly valve, and pivot means connecting the other end cap of said Bourdon tube to said annular support, said pivot means being rigidly connected to said support for preventing lateral movement of said Bourdon tube. i

4. In combination with a support, a pin mounted on' said support, a member mounted for swinging movement about an axis parallel to said pin, and a Bourdon tube extending nearly a complete circle and having one end pivoted on said pin and the other end pivoted to said swinging member.

5. In combination with a swinging member, means for supporting said member for swinging movement about an axis, a Bourdon tube having one end pivotally connected to said support, a pivot carried by the other end of said Bourdon tube connected to said swinging member, whereby said pivot is movable in an are about the axis of said swinging member. N

6. In a thermostat, in combination with an annular'member, a butterfly valve mounted in said annular member, and aBourdon tube having one end pivoted to said annular member and the other end pivotally connected to said butterfly valve.

7. In a thermostat, in combination with an annular member, a shaft extending transversely of said annular member, a butterfly valve on said shaft, a Bourdon tube having one end pivotally mounted on said annular member and the other end pivoted directly to a rigid portion of said but-.

terfly valve.

8. In a thermostat, in combination with a system for the circulation of cooling medium for an internal combustion engine, an annular member mounted in said cooling system, a butterfly valve for closing said annular member, a casing defining an expansible chamber, said casing having one end pivoted on said annular member and the other end pivoted to said valve, and fllled with a material which melts and expands abruptly at a critical point in the cooling system temperature.

GEORGE R. BL'ODGETT. 

